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kondaur [170]
2 years ago
14

Why does the pink color, which forms at the point where NaOH comes into contact with the solution (HCl) in the flask, disappear

more slowly near the endpoint?
Chemistry
1 answer:
Novay_Z [31]2 years ago
4 0
Answer is: because pH value of solution is changing.
Balanced chemical reaction: NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l).
pH of sodium hydroxide solution is above seven (basic), when solution of hydrochloric acid is added, pH slowly dropping until it became neutral solution (pH is equal seven) and that is endpoint of titration.
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Write the net ionic equation for the reaction of zinc metal with aqueous iron(II) nitrate. Include physical states.
kotykmax [81]

Answer:

Zn°(s) + Fe⁺²(aq)  => Zn⁺²(aq) + Fe°(s)

Explanation:

Molecular Equation:

Zn°(s) + Fe(NO₃)₂(aq) => Zn(NO₃)₂(aq) + Fe°(s)

Ionic Equation:

Zn°(s) + Fe⁺²(aq) + 2NO₃⁻(aq) => Zn⁺²(aq) + 2NO₃⁻(aq) + Fe°(s)

Net Ionic Equation: => Drop NO₃⁻ as spectator ion

Zn°(s) + Fe⁺²(aq)  => Zn⁺²(aq) + Fe°(s)

7 0
2 years ago
Why a slow growing forest can have a very low NPP and yet store a massive amount of biomass.
drek231 [11]
Net Primary Productivity ... the amount of biomass present in an ecosystem at a particular time .... Explain why a slow growing forest can have a very low NPP and yet store a massive amount of biomass.
8 0
2 years ago
"The elementary reaction 2 NO2(g) → 2 NO(g) + O2(g) is second order in NO2 and the rate constant at 600 K is 6.77 × 10-1 M-1s-1.
blsea [12.9K]

Answer : The half-life at this temperature is, 3.28 s

Explanation :

To calculate the half-life for second order the expression will be:

t_{1/2}=\frac{1}{k\times [A_o]}

When,

t_{1/2} = half-life = ?

[A_o] = initial concentration = 0.45 M

k = rate constant = 6.77\times 10^{-1}M^{-1}s^{-1}

Now put all the given values in the above formula, we get:

t_{1/2}=\frac{1}{6.77\times 10^{-1}M^{-1}s^{-1}\times 0.45M}

t_{1/2}=3.28s

Therefore, the half-life at this temperature is, 3.28 s

7 0
2 years ago
Zinc sulfide reacts with oxygen according to the reaction 2ZnS(s)+3O2(g)→2ZnO(s)+2SO2(g) A reaction mixture initially contains 5
LenKa [72]

Answer:

The answer to your question is: Excess oxygen = 2.3 mol

Explanation:

Data

ZnS = 5 mol

O2 = 9.8 mol

Excess reactant = ?

Balanced reaction

                                 2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g)

MW ZnS = 65 + 32 = 97 x 2 = 194 g

MW O2 = 16 x  6 = 96 g

                           2 mol of ZnS  ------------------- 3 mol O2

 

Ratio from the reaction = 3 mol O2/ 2 mol ZnS

                                      = 1.5

Ratio from the quantities in the experiment = 9.8 mol O2 / 5 mol of ZnS

                                                                        = 1.96

Excess reactant = Oxygen because the ratio increases

                             

                                2 mol of ZnS  ------------------- 3 mol O2

                                5 mol of ZnS  -------------------  x

                                x = (5 x 3) / 2

                               x = 7.5 mol of O2

Excess Oxygen = 9.8 mol - 7.5 mol

Excess oxygen = 2.3 mol

4 0
2 years ago
What mass of fes is formed if 9.42 g of fe reacts with 68.0 g of s8? 8fe(s) + s8(s) → 8fes(s)?
allochka39001 [22]
From the equation, we see that the molar ratio of Fe : S required is:

8 : 1

The moles of Fe present are: 9.42/56 = 0.168
Moles of S = 68/(32 * 8) = 0.265

The molar ratio is:

1 : 1.6

Therefore, iron is the limiting reactant as it is present in a ratio lower than that required. The ratio of

Fe : FeS  is
1 : 1

So 0.168 moles of FeS will form. The mass of FeS will be:

Mass = 0.168 * (56 + 32)
Mass = 14.78 grams

14.78 grams of FeS will be formed.
4 0
2 years ago
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